Gradient Thermal Cyclers

What is the experience to date with so called gradient thermal cyclers
such as the Stratagene RoboCycler Gradient? How dependable is the robot
arm in long term use and how reproducible are temperatures in the
gradient block? Are there competing manufacturers? Has any manufacturer
figured out how to combine the ability to program thermal gradients with
the convenience of a heated lid to prevent condensation? Post replies or
send e-mail to kerppola at umich.edu. Thanks for your help!